I am guessing that the point she was trying to make was that when you have children singly, you can pass some things on or re-use them e.g. cots, prams etc Whereas when you have twins, you can't do that. However, as you say, that is the luck of the draw, I had two kids close together so couldn't do a lot of those things either and maybe you need to compensate families who have kids of different sexes as they can't expect their son to use pink blankets!
I am the youngest of 7, we never had a car at all, my parents worked to support us as it was their choice to have us. When you decide to have a baby, you need to consider in advance what you would do if it is a multiple birth, not just expect the rest of the country to fund it for you. I really do think sometimes that people think that the goverment has money to burn and that actually it is not coming from the taxes that we all pay.